VirtualBox on OSX Host: Signal 6 Error, can only run headless

Question

I am unable to start any of my VMs interactively. They work when run headless however (--type vrdp)

If I try to run normally I get:

$ VBoxManage startvm Kubuntu
Waiting for the VM to power on...
VBoxManage: error: The virtual machine 'Kubuntu' has terminated unexpectedly during startup because of signal 6
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component Machine, interface IMachine, callee 

My host machine is an Intel iMac running 10.6.7, and I'm using VirtualBox 4.0.6 with the Oracle extensions installed.

Any ideas?

Further info: The virtual machines start up just fine interactively if I use sudo. That seems to imply there is some sort of bad permission or locked file or something somewhere, but I have already checked all the files in Library/VirtualBox.

Answer 1

Firstly, backup your VM (including the disk image and everything that goes with it).

Then, go into the folder in which your VM is held. In there, you should see a file called "VirtualBox.xml", and HOPEFULLY, a file called "VirtualBox.xml-prev". Rename the "VirtualBox.xml" file to "VirtualBox.xml.old", and then rename "VirtualBox.xml-prev" to "VirtualBox.xml". Try starting your VM again - the error should be gone.

If you don;'t have a VirtualBox.xml-prev file, then try creating a new VM, and use your old disk image. That process will re-create the VirtualBox.xml file for you.

Remember to back up!